Will diets which derive their protein content from plant vs animal sources have beneficial renal and metabolic effects in individuals with NIDDM and microalbuminuria? This is a crossover study in which each subject serves as his/her own control by eating, in random order, 6 weeks of meals containing animal (meat, milk) and 6 weeks of plant (soy type products) protein. Meals will be prepared in the GCRC, will be nutritionally equivalent except for protein source, and will be eaten at home. Studies will be conducted in the GCRC. Subjects are 24 males and females between the ages of 35 and 75 with NIDDM and microalbuminuria, treated with diet or diet plus oral anti-diabetic medication(s). Main outcome measures are a) fasting and postprandial renal hemodynamics (GFR, RPF), 24-hr urines for urine urea nitrogen, albumin excretion rate, and creatinine; b) fasting total cholesterol, HDL-c, LDL-c and triglyceride, and postprandial triglycerides; c) insulin, glucose, HbA1c, and amino acid profiles. To establish whether plant protein diets are beneficial in long term treatment of high risk individuals with NIDDM, data will be analyzed for dietary effects upon fasting and postprandial renal hemodynamics, hormonal and amino acid profiles, lipid metabolism, and sequential changes in AER.